mpr-6zhmaut-api

Monoprice sells this wacky 6 zone amp with a serial interface. This tiny project wraps the serial interface with a JSON API.

A detailed walk-through is available illustrating the process to use this API easily on a Raspberry Pi

Installation

    npm install
    cp etc/systemd/system/6zhmaut-api.service /etc/systemd/system/6zhmaut-api.service
    systemctl enable 6zhmaut-api
    systemctl start 6zhmaut-api

Environment Variables

DEVICE = <string> - the serial port device name (defaults to /dev/ttyUSB0)

BAUDRATE = <integer> - the baud rate to use to connect to the device (defaults to 9600)

PORT = <integer> - port for API to listen on (defaults to 8181)

AMPCOUNT = <1|2|3> - the number of amps (you can slave up to two additional amps) (defaults to 1)

REQUERY = <true|false> - re-query the keypads before responding to a /zones request (defaults to false)

CORS = <true|false> - respond to a CORS request with an Access-Control-Allow-Origin=* (defaults to false)

Running the server

PORT=8181 npm start

or using more environment variables:

PORT=8181 AMPCOUNT=2 REQUERY=false BAUDRATE=115200 CORS=false npm start

Updating the Baud Rate

You can update the baud rate of the controller to one of the following rates: 9600, 19200, 38400, 57600, 115200, 230400

By default, at power loss, the device is set to run at 9600 BAUD. You can adjust it using the updateBaudRate.js via npm run-script (or directly with node).

OLDBAUDRATE=9600 NEWBAUDRATE=115200 npm run-script baudrate

Notes:

• To reset the baud rate remove power from the controller for 30 seconds - it will reset to 9600 BAUD
• Running npm run-script baudrate with the incorrect connection baud rate will not cause it to lock so intialization scripting could be created to reset the baudrate before the API enables.

Environment Variables for updateBaudRate.js

DEVICE = <string> - the serial port device name (defaults to /dev/ttyUSB0)

OLDBAUDRATE = <integer> - the current baud rate of the controller (the rate used to initially connect to the device)

NEWBAUDRATE = <integer> - the desired baud rate

API

GET /zones

[
  {
    "zone": "11",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "15",
    "tr": "10",
    "bs": "10",
    "bl": "10",
    "ch": "01",
    "ls": "00"
  },
  {
    "zone": "12",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "15",
    "tr": "10",
    "bs": "10",
    "bl": "10",
    "ch": "01",
    "ls": "00"
  },
  {
    "zone": "13",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "15",
    "tr": "10",
    "bs": "10",
    "bl": "10",
    "ch": "01",
    "ls": "00"
  },
  {
    "zone": "14",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "10",
    "tr": "10",
    "bs": "12",
    "bl": "10",
    "ch": "02",
    "ls": "00"
  },
  {
    "zone": "15",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "20",
    "tr": "07",
    "bs": "07",
    "bl": "10",
    "ch": "01",
    "ls": "00"
  },
  {
    "zone": "16",
    "pa": "00",
    "pr": "01",
    "mu": "00",
    "dt": "00",
    "vo": "21",
    "tr": "07",
    "bs": "07",
    "bl": "10",
    "ch": "01",
    "ls": "00"
  }
]

GET /zones/:zone

Returns the current status of a specific zone.

{
  "zone": "11",
  "pa": "00",
  "pr": "01",
  "mu": "00",
  "dt": "00",
  "vo": "15",
  "tr": "10",
  "bs": "10",
  "bl": "10",
  "ch": "01",
  "ls": "00"
}

GET /zones/:zone/:attribute

Return the value of a specific attribute in a zone as plain text. Valid attributes are:

pa (send zone 1 to all outputs)
power / pr
mute / mu
do not disturb / dt
volume / vo
treble / tr
bass / bs
balance / bl
channel / source / ch
keypad status / ls

$ curl 192.168.1.254:8181/zones/11/bass
10

POST /zones/:zone/:attribute

Update a zone's attribute using the plain-text value of the body.

pa (send zone 1 to all outputs)
power / pr
mute / mu
do not disturb / dt
volume / vo
treble / tr
bass / bs
balance / bl
channel / source / ch

Here's an example where we turn the bass of zone 11 up:

$ curl 192.168.1.254:8181/zones/11
{"zone":"11","pa":"00","pr":"01","mu":"00","dt":"00","vo":"15","tr":"10","bs":"10","bl":"10","ch":"01","ls":"00"}
$ curl -X POST -d '12' 192.168.1.254:8181/zones/11/bass
{"zone":"11","pa":"00","pr":"01","mu":"00","dt":"00","vo":"15","tr":"10","bs":"12","bl":"10","ch":"01","ls":"00"}

Device Manual

The manual for the 6 zone amp is available (via Monoprice)[https://downloads.monoprice.com/files/manuals/10761_Manual_141028.pdf]

Contributions

• fork
• create a feature branch
• open a Pull Request